Pressure control valve

Abstract

A pressure control valve has a spool slidably mounted in a valve body. The valve body has a chamber between opposed lands of the spool. An oil guide is provided in the chamber. The oil guide has a passage arranged to apply oil pressure to the lands. The passage has a small cross-sectional area so as to reduce pulsation of oil pressure.

What is claimed is: 
     
       1. A pressure control valve comprising a valve body having opposite land-engaging portions,   a spool having a first land and a second land spaced opposite each other, said spool is slidably mounted at the land-engaging portions in said valve body at the lands,   said valve body defining an annular chamber between the land-engaging portions and between the first and second lands of said spool, the annular chamber having a larger outer diameter than that of the first and second lands,   a passage formed in the valve body communicating with said annular chamber so as to apply oil pressure to said first and second lands, and   oil guide means secured in the passage for reducing the cross-sectional area of the passage to increase resistance of the passage so as to reduce noise.   
     
     
       2. The pressure control valve according to claim 1, further comprising a spring urging said spool in a direction.   
     
     
       3. The pressure control valve according to claim 2, wherein said first land is formed to applied with said oil pressure at one side thereof in another direction opposite the direction of urging of said spring.   
     
     
       4. A pressure control valve according to claim 1, wherein said oil guide means is made of an elastic material embedded in the annular chamber.   
     
     
       5. A pressure control valve according to claim 1, wherein said oil guide means is made of resin.   
     
     
       6. A pressure control valve according to claim 1, further comprising an automatic transmission, and wherein   said control valve is operatively connected to said automatic transmission so as to control said automatic transmission.   
     
     
       7. A pressure control valve according to claim 6, wherein said control valve is a line pressure control valve, and wherein   an oil pump communicate with said passage.   
     
     
       8. A pressure control valve according to claim 7, further comprising a spring urging said spool in a direction,   means for acting on said spring in dependency on the transmission ratio of the transmission.   
     
     
       9. A pressure control valve according to claim 8, wherein said transmission is a continuously variable transmission.   
     
     
       10. A pressure control valve according to claim 1, wherein said oil guide means comprises an annular portion disposed in said annular chamber and forming a hole in which said first land is slidably engaged and a portion radially depending from said annular portion, said radially depending portion extending in said passage and having thick side portions and a thin portion centrally connecting said side portions and extending from said hole to a position spaced from a free end of said thick side portions forming a groove between said free ends of said thick side portions and a free end of said thin portion between said side portions, said thin portion dividing said passage into two narrow radial oil passages on respective sides of said thin portion between said thick side portions, said two narrow radial oil passages communicating through said groove, whereby the oil pressure is applied to sides of said lands through said radial oil passages, said groove and said hole.   
     
     
       11. A pressure control valve according to claim 10, further comprising an oil pump communicating with said passages.   
     
     
       12. A pressure control valve according to claim 10, wherein said first land is larger than said second land and said hole is essentially equal in diameter to said first land.   
     
     
       13. A pressure control valve according to claim 1, wherein said oil guide means is also secured in said annular chamber.